300 Scientists Engage in Updating Priority Pathogen List

With the aim of strengthening global preparedness and response of any future epidemics and pandemics, as many as 300 scientists will engage in updating the list of priority pathogens that can cause future outbreaks or pandemics.

Starting with a meeting held last Friday, 18 November, WHO is convening over 300 scientists who will consider the evidence on over 25 virus families and bacteria, as well as “Disease X.”

Disease X is included to indicate an unknown pathogen that could cause a serious international epidemic. The experts will recommend a list of priority pathogens that need further research and investment. The process will include both scientific and public health criteria, as well as criteria related to socio-economic impact, access, and equity.            


The list was first published in 2017 and the last prioritization exercise was done in 2018. The current list includes COVID-19, Crimean-Cong haemorrhagic fever, Ebola virus disease and Marburg virus disease, Lassa fever, Middle East respiratory syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS), revised list is expected to be published in the first quarter of 2023. Nipah and henipaviral diseases, Rift Valley fever, Zika and Disease X.

WHO’s Health Emergencies Programme Executive Director Dr Michael Ryan said, “targeting priority pathogens and virus families for research and development of countermeasures is essential for a fast and effective epidemic and pandemic response. Without significant R&D investments prior to the COVID-19 pandemic, it would not have been possible to have safe and effective vaccines developed in record time.”


For those pathogens identified as priority, the WHO R&D Blueprint for epidemics develops R&D roadmaps, which lay out knowledge gaps and research priorities. Where relevant, target product profiles, which inform developers about the desired specifications for vaccines, treatments and diagnostic tests, are developed. Efforts are also made to map, compile and facilitate clinical trials to develop these tools. Complimentary efforts – such as to strengthen regulatory and ethics oversight – are also considered.

WHO Chief Scientist Dr Soumya Swaminathan said, “This list of priority pathogens has become a reference point for the research community on where to focus energies to manage the next threat. It is developed together with experts in the field, and is the agreed direction for where we—as a global research community—need to invest energy and funds to develop tests, treatments and vaccines. We thank our donors like the US government, our partners, and the scientists who work with WHO to make this possible.”

The prioritization exercise will draw on the lessons from COVID-19 and ensure that trust, equity and access for those at highest risk is central to future R&D efforts. It will adopt a viral family approach to identify representative viruses (or prototypes) within a viral family as a pathfinder in generating science, evidence and filling knowledge gaps that may then be applicable to other viruses of threat in the same  family. In recent years there has been growing support for this approach as it offers a framework to fast-track research and encourages research efforts on entire classes of viruses (e.g. flaviviruses), instead of just individual strains (e.g. zika virus), thus improving the capability to respond to unforeseen strains, zoonotic viruses (an animal virus that could jump to humans) and the potential threat of a Disease X.

The revised list is expected to be published in the first quarter of 2023.


Please enter your comment!
Please enter your name here